Method of fabricating a finned heat exchanger tube

ABSTRACT

A heat exchanger embodying an elongated tubular member with integral elongated fins extending transversely thereacross and projecting outwardly therefrom, the fins terminating at their outer longitudinal edges in spaced spines.

United States Patent I [1 1 O Connor *Jan. 1, 1974 METHOD OF FABRICATING A FINNED HEAT EXCHANGER TUBE [75] Inventor: Joseph M. OConnor, Chicago, 111.

[73] Assignee: Peerless of America, Incorporated,

Chicago, Ill.

The portion of the term of this Notice:

patent subsequent to Sept. 19, 1989, has been disclaimed.

[22] Filed: Apr. 24, 1972 211 Appl. No.: 247,109

Related U.S. Application Data [60] Division of Ser. No. 68,910, Sept. 2, 1970, Pat. No. 3,692,105, which is a continuation-in-part of Ser. No. 34,715, May 5, 1970.

[52] U.S. Cl. 29/l57.3 B, 29/157.3 A, 29/157.4,

Primary ExaminerRichard .1. Herbst Assistant ExaminerD. C. Reiley, 111 AttorneyRoot & OKeeffe [57] ABSTRACT A heat exchanger embodying an elongated tubular member with integral elongated fins extending transversely thereacross and projecting outwardly therefrom, the fins terminating at their outer longitudinal edges in spaced spines.

72/325 [51 Int. Cl B2ld 53/02, B23p 15/26 3 Claims, 7 Drawing Figures PATENTEUJAN 11am SHtEI 1 I]? 2 1 METHOD OF EABRICA'TING A FINNED HEAT EXCHANGER TUBE CROSS-REFERENCETO RELATED APPLICATION This application is adivisionof my earlier filed, pending application, Ser. No. 68,910, filed in the. U.S. Patent Office on Sept.. 2, 1970, now U.S. Pat. No. 3,692,105, issued Sept. 1.9, I972 which wasa continuation-impart of my earlier filed application, Ser. No. 34,715, filed in the US. Patent Office on May 5, 1970.

BACKGROUND- OF THE INVENTION This invention relates to heat exchangers, and, more particularly, to heat exchangers of the spined type.

It is a primary object of the present invention to afford a novel heat exchanger and a novel method of making the same.

Another object is to afford a novel finned heat exchanger wherein the fins are formed by cutting or gouging the same from wall portions of the heat exchanger.

Another object of the present invention is to enable a novel heat exchanger to be afforded in a novel and expeditious manner wherein secondary heat transfer surfaces may be formed by cutting or gouging them out of ribbed tubular stock to afford fins having outwardly projecting spines.

Heat exchangers embodying spines formed from outwardly projecting ribs on a tubular member have been disclosed R. W. Kritzer U.S. Pat. No. 3,202,212. Heat exchangers of the type disclosed in the aforementioned Kritzer patent have proven to be very effective. However, it is an object of the present invention to afford improvements overheat exchangers of the type disclosed in the aforementioned Kritzer patent.

Another object of the present invention is to afford a novel heat exchanger of the spined type wherein the spines are constituted and arranged in a novel and expeditious manner.

An object ancillary to the foregoing is to afford such a heat exchanger wherein the. spines are formed. as an integral part of larger fin members.

A further object of the present invention is to afford a novel heat exchanger of the spaced fin type which embodies fins constitutedv and arranged in a novel and expeditious manner on a: tubular member to afford effective reinforcing of the tubular member against distortion from internal pressures, andv the like.

Another object is to afford a novel, elongated heat exchanger of the spaced fin type which embodies elongated fins extending transversely to the length of the heat exchanger in position to afford an effective reinforcing beam effect to the heat exchanger.

Another object is to enable a serpentine-shaped heat exchanger to be reinforced in a novel and expeditious manner.

Yet another object of the present invention is to afford a novel, elongated tubular heat exchanger, having reverse bends therein, wherein the bends are reinforced against necking in of the outside surface thereof in a novel and expeditious manner.

A further object is to afford anovel, elongated, tubular heat exchanger having reverse bends therein, with spaced transversely extending ribs projecting from the inner and outer surfaces of the bends, and with the fins on the inner surfaces constituted and arranged in a novel and expeditious manner for the reception of fastening members through the bends.

Another object is to afford a novel heat exchanger of the aforementioned type which is practical and efficient in operation, and which. may be readily and economically produced commercially.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

SUMMARY OF THE INVENTION The present invention affords a novel heat exchanger which embodies an elongated tubular member having a wall portion from which elongated fins extend transversely thereacross and project outwardly therefrom,

with spaced spines projecting outwardly from the fins DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view of a length of heat exchanger element embodying the principles of the present invention;

FIG. 2 is a longitudinal sectional view taken substantially along the line 22 in FIG. 1;

FIG. 3 is a transverse sectional view taken substantially along the line 3-3 in FIG. 1;

FIG. 4 is a side elevational view of a modified form of the present invention;

FIG. 5 is an enlarged, fragmentary view of a portion of the heat exchanger shown in FIG. 4;

FIG. 6 is a detail sectional view taken substantially along the line 6-6 in FIG. 5; and

FIG. 7 is a detail sectional view taken substantially along the line 7-7 in FIG. 4.

DESCRIPTION OF THE EMBODIMENTS SHOWN HEREIN A heat exchanger element 1 embodying the princi ples of the invention, is shown in FIGS. l-3 of the drawings as one end portion of an elongated tubular member 2, to illustrate the presently preferred embodiment of the present invention, and to illustrate the presently preferred method of making heat exchangers in accordance with the principles of the present invention.

As will be discussed in greater detail hereinafter, in the preferred practice of the present invention the heat exchanger element 1 is preferably formed from a suitable length of tubular stock, such as the tubular memher 2, working from one end portion A of the tubular member 2, FIG. 2, toward the other end B thereof, and severing the heat exchanger 1 from the remainder B-C of the tubular member 2 upon completion of the forming of the desired length of heat exchanger, such as the length A-C.

The heat exchanger element 1 embodies, in general, an elongated, tubular body portion 2a having elongated fins 3 projecting outwardly therefrom, each of the fins 3 embodying an elongated base portion 4 having a plurality of spines 5 projecting outwardly from one longitudinal edge thereof, FIG. 1.

The tubular member 2 shown in the drawings is substantially rectangular in transverse cross section, embodying a top wall 6 and a bottom wall 7 disposed in substantially parallel relation to each other, and two oppositely disposed side walls 8 and 9 extending between respective ends of the walls 6 and 7 in substantially perpendicular relation thereto. An opening 10 extends longitudinally through the tubular member 2. As will be appreciated by those skilled in the art, the tubular member 2 is shown in FIGS. 1-3 as being rectangular in transverse cross section and having a single opening 10 extending therethrough merely by way of illustration and not by way of limitation, and tubular members having shapes other than rectangular and having a plurality of openings extending longitudinally therethrough may be afforded without departing from the purview of the present invention.

In the heat exchanger 1 shown in the drawings, the fins 3 project outwardly from the outer faces of two walls 6a and 7a, FIG. 2, corresponding to, and, in fact, formed from the walls 6 and 7 of the tubular member 2, as will be discussed in greater detail presently. The fins 3 extend longitudinally across the respective walls 6a and 7a in substantially transverse relation to the length of the tubular body portion 2a, and each of the fins 3 embodies one of the aforementioned base portions 4, having a lower longitudinal edge portion 11 integral with the respective wall 6a and 7a to which it is attached. Each base portion 4 projects outwardly from the respective wall 6a or 7a, preferably in substantially perpendicular relation thereto, with the spines 5 thereon spaced along and projecting outwardly from the longitudinal edge of the base portion 4 remote from the body portion 2a. Each of the spines 5, FIG. 2, embodies a surface 12 sloping outwardly from the base portion 4 from which it projects, to afford an enlarged portion 13, and another surface 14 sloping inwardly from the enlarged portion 13 and terminating at the outer edge of the spine 5 in a thin edge 15.

The tubular member 2, from which the heat exchanger l, shown in the drawings is made, is of any suitable material, such as, for example, aluminum, and embodies a plurality of elongated, outwardly projecting ribs 16 on the outer face of each of the side walls 6 and 7, the ribs 16 extending longitudinally of the tubular member 2 in parallel spaced relation to each other.

In making the heat exchanger 1, a tubular member such as the tubular member 2, and embodying the ribs 16 extending the full length thereof may first be formed. Thereafter, the fins 3 may be successively formed on each of the side walls 6 and 7 from one end portion of the tubular member 2, such as the end portion A toward the other end B thereof, FIG. 2. The fins 3 may each be cut or gouged from the walls 6 and 7 by means of a suitable cutting tool which first cuts along lengthwise of the ribs 16, to the right, as viewed in FIG. 2, to form the surface 17 which terminates at its lower end, as viewed in FIG. 2, at the base 18 of the ribs 16, the cutting tool then continuing to cut along lengthwise of the portion 19 of the wall 6 or 7 underlying the ribs 16, to form the surface 20, FIG. 2. The fin 3, which has been cut or gouged from the body portion 2, is then bent outwardly preferably to a position approximately perpendicular to the plane of the wall 6 or 7 on which it is formed. This gives each fin, after the first fin has been cut or gouged, the aforementioned configuration as illustrated in FIG. 2. If desired, after completion of the forming of the fins 3, the body portion 2 may be cut off to the left, as viewed in FIG. 2, of the aforementioned first fin, not shown, so that all fins 3 on the finished product have the aforementioned configuration.

After thus forming the fins 3 along the desired length of the tubular member 2, such as the length A C, the tubular member 2 may be severed transversely to its length at the point C to thereby afford a finished heat exchanger element having fins 3 extending substantially the full length thereof. As will be appreciated by those skilled in the art, if desired, the formation of the fins 3 may be commenced inwardly of the end portion A of the tubular member 2, and the tubular member 2 may be severed outwardly to the left, as viewed in FIG. 2, of the last formed fin 3 to thereby afford end portions which project outwardly from the outermost fins 3 to afford connecting members at each end of the finished heat exchanger. In such last mentioned construction, not shown, the ribs 16 of the tubular member 2 disposed outwardly of the aforementioned outermost fins, preferably are removed by suitable means, such as, for example, grinding, to thereby afford a smoothwalled end portion for the completed heat exchanger.

In FIGS. 4-7 of the drawings a heat exchanger 101 is shown to illustrate a modified form of the present invention, parts which are the same as the parts of the heat exchanger 1 shown in FIGS. 1-3 being indicated by the same reference numerals.

In the heat exchanger 101, FIG. 4, the tubular body portion 102a has been bent into a serpentine pattern embodying reverse bends 21. The spines 3, which project outwardly from the opposite side walls 6a and 7a of the tubular body portion 102a are formed in the same manner as heretofore disclosed with respect to the heat exchanger 1, while the tubular member 102, from which the tubular body portion 102a is formed, is in substantially straight condition, with the fins 3 being formed in spaced relation to the ends A and B of the tubular member 102, to thereby afford end portions 22 and 23 for use as connecting members at each end of the completed heat exchanger 101. If desired, the ribs 16 embodied in the tubular member 102 in its original form may be removed from the end portions 22 and 23 to thereby afford a smooth walled connecting member at each end of the heat exchanger 101.

The fins 3 may be of any desired, suitable thickness. However, preferably, in a heat exchanger of the type shown in FIGS. 4-7, the fins 3 are in the nature of ten thousandths to thirty thousandths of an inch thick, with the fins spaced from each other a distance of onesixteenth to one-third of an inch, respectively.

After the tubular member 102, with the fins 3 formed thereon has been into the serpentine pattern shown in FIG. 4, the fins 3 on the inner faces of the return bends 21 may be brushed or otherwise suitably moved into compacted form, as shown at 24 in each of the return bends 21. In such form, the fins 3 disposed along the inner curved surfaces of the return bends 21 are disposed in juxtaposition to each other to thereby afford an opening 25 through each of the return bends 21. With this construction, suitable braces, such as the braces 26 and 27, FIG. 4, may be mounted on one side of the tubular body portion 102a, and braces 28 and 29 may be mounted on the other side of the tubular body portion 2a in parallel relation to the braces 26 and 27, respectively, with suitable fastening members, such as bolts 30, extending through the openings 25 in the return bends 21 and securing the braces 26 and 27 to the braces 28 and 29, respectively.

It has been found that with fins, such as the fins 3, formed on a tubular member, such as the tubular member 102, in accordance with the principles of the present invention, the fins 3, extending traversely across the length of the tubular member 102, afford a reinforcing beam effect which is effective to prevent collapsing or necking in of the tubular member 102 during formation of bends therein such as the aforementioned return bends 21, even in tubular members not embodying internal ribs.

In FIG. 4, the tubular member 102 is shown as embodying a plurality of longitudinally extending passageways 31. The walls 32 separating the passageways 3-1 are of assistance in preventing the collapse or necking in of the tubular member 102 during formation of the reverse bends 21. However, such walls are not essential to the practice of the present invention and it will be appreciated that the heat exchanger 101 may embody a single-port tubular member, such as shown in FIGS. l-3 without departing from the purview of the present invention.

With the heat exchanger 1 constructed in the aforementioned manner, it will be seen that the fins 4 afford secondary heat transfer surfaces, which are relatively thin and embody points and edges to thereby afford highly efficient heat transfer between the heat exchanger 1 and the atmosphere or working fluid with which it is surrounded.

In addition, it will be seen that the present invention affords a novel heat exchanger of the spined type wherein the portions of the heat exchanger to which the spines are attached not only afford good heat transfer to and from the spines, but afford effective transverse reinforcement for the tubular body portion of the heat exchanger.

In addition, it will be seen that the present invention affords a novel heat exchanger which is practical and efficient in operation and which may be readily and economically produced commercially.

Further, it will be seen that the present invention affords a novel method of making a finned type of heat exchanger.

Thus, while I have illustrated and described the preferred embodiments of my invention, it is to be understood that these are capable of variation and modification, and I therefore to not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

l. The method of making a heat transfer element, comprising a. forming an elongated tubular member having a wall portion with spaced, outwardly projecting elongated ribs extending longitudinally of said tubular member, and

b. successively, from one end portion of said tubular member toward the other end portion thereof,

1. cutting fins from said ribs and the underlying portions of said wall portion to thereby afford a. elongated base portions 1. extending across a plurality of said ribs transversely to the length of said tubular member, and 2. directly attached to said underlying wall portions, and b. spines spaced along said base portions and projecting outwardly therefrom, and

2. turning said fins outwardly into outwardly pro: jecting relation to said underlying wall portions.

2. The method of making a heat transfer element as defined in claim 1, and in which a. said fins are formed on two oppositely disposed longitudinally extending faces of said tubular member, and

b. said tubular member, after said fins are formed thereon is bent upon itself to form a return bend having said faces, with said fins thereon, on the inside and outside of said bend.

3. The method of making a heat transfer element as defined in claim 2, and in which a. said tubular member is formed without any inter nal reinforcing ribs. 

1. The method of making a heat transfer element, comprising a. forming an elongated tubular member having a wall portion with spaced, outwardly projecting elongated ribs extending longitudinally of said tubular member, and b. successively, from one end portion of said tubular member toward the other end portion thereof,
 1. cutting fins from said ribs and the underlying portions of said wall portion to thereby afford a''. elongated base portions 1''. extending across a plurality of said ribs transversely to the length of said tubular member, and 2''. directly attached to said underlying wall portions, and b''. spines spaced along said base portions and projecting outwardly therefrom, and
 2. turning said fins outwardly into outwardly projecting relation to said underlying wall portions.
 2. turning said fins outwardly into outwardly projecting relation to said underlying wall portions.
 2. The method of making a heat transfer element as defined in claim 1, and in which a. said fins are formed on two oppositely disposed longitudinally extending faces of said tubular member, and b. said tubular member, after said fins are formed thereon is bent upon itself to form a return bend having said faces, with said fins thereon, on the inside and outside of said bend.
 3. The method of making a heat transfer element as defined in claim 2, and in which a. said tubular member is formed without any internal reinforcing ribs. 